The present invention relates to a brake device for elevator, and more particularly, a brake device for elevator by use of hydraulic pressure generated by fall in construction work or building to enable the brake pad to brake the elevator, thereby preventing free fall or crash accident of the elevator.
Conventional elevator used in construction work is constructed such that the elevator is lifted upwards and downwards along the multi-stage assembled block as shown in FIGS. 1 to 3.
The elevator car 1 has a pair of guide rail rollers 1a for moving along a guide rail 6 of the block 5. Two guide rail rollers 1a are disposed at front and rear with respect to the guide rail 6, to guide the elevator upwards and downwards. A hook 1b is disposed to guide the guide rail 6, for preventing deviation of the elevator car 1.
A plurality of motors 2 and pinions 2a are employed in the elevator car 1, for actuating the elevator to be lifted in any desired direction. A plurality of racks 4 is disposed at the block 5 in the vertical direction. Driving of the motor 2 allows the pinions 2a to be rotated along the racks 4, so that the elevator car 1 is lifted upwards and downwards.
Especially the elevator car 1 for use in construction work is required to attention safety since the elevator car is exposed at all times, and nevertheless the brake device is most important.
Conventional brake device of the elevator shows use of a governor 3. The governor-braking device utilizes centrifugal force, in which the pinion 3a of the governor 3 for brake device is engaged with the rack 4 at the block. To the pinion a centrifugal weight is connected.
In case of fall or crash of the elevator due to abnormality such as malfunction or etc., the pinion 3a of the governor 3 of the elevator is rotated at high speed by the rack 4, so that centrifugal weight being spread becomes held onto boss in the brake device to stop the pinion 3a and to brake the elevator car 1.
Because lifting operation of the elevator car 1 is dependent on pinion 2a and rack 4, the longer the elevator is used, the more fatigue the rack and pinion receive. The governor 3 intends to stop the elevator in crash but the rack weakened by fatigue practically receives a heavy impact. As a result, the gear teeth of the rack 4 or pinion 3a of the governor 3 become damaged, resulting in fall or crash accident of the elevator. In a normal working condition, the elevator moves smoothly and impact does not harm on the passenger or luggage. However, in case of crash of elevator, heavy impact is accompanied with stop of the elevator by the governor, resulting in severe damage on luggage or passengers.
The building elevator operated by rope also utilizes the brake device by governor.
This construction has a disadvantage of damage of passenger or luggage by heavy impact in stopping the elevator being fallen down.
The present invention is derived to solve the disadvantage of the conventional art and to generate hydraulic pressure after detecting free fall or crash of the elevator and actuate a brake pad by hydraulic pressure, so that impact by sudden brake is relieved to maintain a stable brake interval and prevent the brake device from being damaged by heavy impact caused by sudden brake.
The object of the present invention is accomplished by providing a hollow box-shaped elevator car 1 for holding the passenger or luggage; block 5 including a pair of guide rails 6 for guiding upwards and downwards the elevator car 1; a plurality of racks 4 disposed at the block 5 along the lifting direction in vertical; at least one motor 2 tooth-engaged with at least one pinion 2a at the racks 4, for lifting upwards and downwards the elevator car 1; a clutch 12 for controlling power transmission to connect a driving shaft 19 to a driven shaft 20 when the pinions 2a and 11 engaged with the racks 4 are rotated at high speed due to elevator drop; hydraulic pump 15 for generating hydraulic pressure from power transmission though a plurality of transmission gears 13 when the clutch 12 delivers rotation; and a plurality of hydraulic cylinders 17 for braking the elevator by brake pad 18 in tight coupled with the guide rails 6 by hydraulic power from the hydraulic pump 15.
In crash of the elevator, the clutch actuates to operate the brake pad by hydraulic power from the hydraulic pump, thereby receiving impact and protecting passengers or luggage in the elevator.
The elevator is stopped by friction brake with less impact onto the passenger or luggage, so that safety and reliability are improved.